Organic matter (OM)-hosted pores play important roles in controlling the porosity and gas content of gas shales. However, the control of organic pore development and preservation remains poorly understood, partly because of the inability to distinguish OM types under the scanning electron microscope (SEM). In this study, seven over-mature Wufeng-Longmaxi Shale samples (equivalent vitrinite reflectance 1.93%–3.07%) were investigated with organic petrography and scanning electron microscope to study the origin of OM and development of organic pores in this black shale succession. Correlative light and electron microscopy was employed to examine pore development in individual macerals. Organic petrographic observations show that OM in these over-mature black shales is dominated by pyrobitumen and graptolites (> 90 vol% of total OM based on point counting). Pyrobitumen mainly occurs as matrix bitumen in the fine-grained matrix, and also as a mixture with clay minerals and fossil cavity infillings. Vitrinite-like particles are minor constituents of OM in the Wufeng-Longmaxi Shale, and their average reflectance, reflectance distribution, and morphology suggest that they may be derived from graptolite fragments lacking diagnostic features and acritarchs. OM type critically controls the development of organic pores. Organic pores primarily occur in pyrobitumen, whereas other macerals are mostly non-porous when examined under the SEM. Results of this study provided important insights into OM thermal evolution and organic pore development in source-rock reservoirs, calling for a critical appraisal of OM in black shales with organic petrography in addition to SEM.

有机质（OM）孔隙在控制气页岩孔隙度和含气量方面发挥着重要作用。然而，对有机孔发育和保存的控制仍然知之甚少，部分原因是在扫描电子显微镜 (SEM) 下无法区分 OM 类型。本研究采用有机岩相学和扫描电镜研究了7个过成熟五峰-龙马溪页岩样品（等效镜质体反射率1.93%~3.07%），研究了该黑色页岩层序中有机质成因和有机孔隙发育情况。相关光学和电子显微镜被用来检查单个macerals 中的孔发展。有机岩相观察表明，这些过熟黑色页岩中的有机质以焦沥青和笔石为主（> 基于点计数的总 OM 的 90 vol%）。焦沥青主要以细粒基质中的基质沥青形式存在，也以与粘土矿物和化石空腔填充物的混合物形式存在。镜质体颗粒是五峰-龙马溪页岩中 OM 的次要成分，它们的平均反射率、反射率分布和形态表明它们可能来源于缺乏诊断特征和记号的笔石碎片。OM 类型严格控制有机质孔隙的发育。有机孔主要出现在焦沥青中，而在 SEM 下检查时，其他物质大多是无孔的。这项研究的结果为烃源岩储层中 OM 热演化和有机孔隙发育提供了重要的见解，